Geologic Unit: Williams Fork

Usage:

Williams Fork Formation of Mesaverde Group (CO*,UT*)

Subunits:

(alphabetical): Bowie Shale Member (CO), Holderness Member (CO), Lion Canyon Sandstone Member (CO*), Paonia Shale Member (CO), Twentymile Sandstone Member (CO*).

Geologic age:

Late Cretaceous*

Type section, locality, area and/or origin of name:

Not designated. Named from exposures along Williams Fork near its junction with Yampa River, and in Williams Fork Mountains, Moffat Co., CO (Hancock, 1925).

AAPG geologic province:

Green River basin*
Piceance basin*
Eagle basin*